1. Field of the Invention
This invention relates to control of document feeder systems for use with copier systems generally, and more specifically to the control of at least two document feeders such that a prior task being run on either of the two document feeders will be suspended, to allow a subsequent or urgent task to be run on the other one of the two document feeders immediately thereafter, and upon the completion thereof, to re-commence the prior task immediately without further operator intervention.
2. Description of the Prior Art
Heretofore, various techniques have been advanced to improve the utility of electrophotographic copiers, duplicators, printers, card-handlers and like machines. One such technique has been to provide more than one input mode and/or device to the host machine so that each input mode and/or device corresponds and is dedicated to a specific predetermined job or task in the belief that, in this way, each task is handled in a more effective manner.
An important, but more general application, of the foregoing technique is disclosed in the previously cited related U.S. Application to Andrews et al. Andrews et al disclose a copy production machine having two input modes. The modes are print mode and copy mode.
In the print mode, word processing techniques, in conjunction with one of a plurality of imaging sources operate such that original images generated thereby are automatically manipulated to produce a set of copies according to the original images. In the copy mode, electrophotographic copying techniques, in conjunction with a semi-automatic document feeder (SADF) device operates such that a specific number of copies of a single original document are produced at a time. In accordance with the teachings of Andrews et al, a print mode task can be "interrupted" to perform a copy mode task on the SADF. Also, in the print mode, one of the plurality of imaging sources can be selected on a priority basis. Thus, in Andrews et al the input modes and/or devices are dedicated to specific predetermined tasks in order to handle the tasks in a more effective manner with the additional capability of "interrupting" operations of the printing mode (primary) with the copy mode (secondary) using the SADF.
Consequently, there is a need in the prior art generally to provide more than one input device, in the form of document feeders, and, particularly to not limit the operation thereof to any dedicated and predetermined tasks.
A use of plural document feeders as input devices to an electrophotographic copier, having a measure of "interrupt" capability, is disclosed in the previously cited related U.S. Application to Kunz et al. The application to Kunz et al is cited for its value as background material rather than as prior art. With this notion in mind, Kunz et al disclose, in conjunction with an electrophotographic copier, an automatic document feeder (ADF) and a semi-automatic feeder (SADF) interfaced therewith. The ADF is a device, generally understood in its operation, for feeding from a stack of original documents, disposed in a tray thereof, one original document at a time, onto a document viewing glass whereupon a predetermined number of exposures of the original document are made as determined by the selected copy quantity. After these exposures are made, the original document is then fed to an exit area. The SADF is a device, generally understood in its operation, for feeding a single original document placed in its entry tray by an operator one at a time onto a document viewing glass. Thus, in Kunz et al, the ADF is situated directly above the aforementioned document viewing glass such that the feed path therefrom is around a 180.degree. bend onto the document viewing glass. The SADF entry tray is situated adjacent the ADF and document viewing glass such that there is a direct feed path from the entry tray to the document viewing glass. Hence, although two document feeders, configured in a unique manner, are used in Kunz et al as input devices, they are limited in their operation in that each is dedicated to a predetermined task. Thus the mention of an "interrupt" capability is in conjunction with "interrupting" operation of the ADF running a large number of documents to run a small number of documents on the SADF. In this context, it would appear that the ADF is more effectively dedicated to tasks requiring a large number of copies and the SADF is dedicated to tasks requiring a small number of copies. However, there are situations, depending on the makeup of the task, where the SADF rather than the ADF should be the primary or desired feeder, e.g., 999 copies of a single original document. Moreover, while the foregoing task is being run, there are situations where a subsequent or urgent task is better run on the ADF (secondary feeder in this example). This subsequent task, for example, could consist of a stack of ten original documents with a requirement of one or two copies each.
Quite clearly then, there is a need not only to handle tasks in a more effective manner by providing dual document feeders with "interrupt" capability only of the dedicated primary feeder by the dedicated secondary feeder, but a need to be able to "interrupt" operation of either the primary or secondary feeder, respectively, depending on the makeup of the tasks to be run.
Yet another "interrupt" technique using a single recirculating automatic document feeder (RADF) is disclosed in U.S. Pat. No. 4,099,860 to Connin, entitled "Copier/Duplicator Priority Interrupt Apparatus", filed Nov. 8, 1976, patented July 11, 1978, and assigned to Eastman Kodak Company. A RADF, as generally understood, (also termed "collating feeder") can operate in either a collate or noncollate mode to selectively produce collated or noncollated copies of original documents. However, its chief utility is in the collate mode since the need for a collator is eliminated. Herein lies the principal advantage of a RADF over an ADF.
In the collate mode, a stack of original documents, in sequential order from top to bottom, having been placed in the RADF, are fed therefrom singly from the bottom of the stack to a document viewing glass. After being exposed once, each original document is serially fed back in sequence to the top of the stack. This process is continued until all of the original documents are exposed once, thereby producing a single collated copy set. The process is repeated if more than one collated copy set is desired up to the number of sets selected.
In the noncollate mode the original documents are exposed more than once, while on the document viewing glass, up to the number of copies selected by an operator. Of course, in this mode, a collator is needed to produce collated copy sets. In this mode of operation, then, there are no apparent advantages of a RADF over an ADF.
With the foregoing background in mind, the teachings of Connin are best understood by way of an example. Hence, in the collate mode, assume that there are 100 original documents in the stack and that a copy of the first original document is being made, i.e., the first original document is at the document viewing glass. Further, assume that an operator selects the "interrupt" mode at this point in time; however, the "interrupt" mode will not be acknowledged immediately. In fact, when the copy of the original document at the document viewing glass, i.e., the first original document is made, it is returned to the top of the stack and the next original document is fed to the document viewing glass and so up to the 100th original document. Thus, the total set is completed, i.e., the copy of the 100th original document is made, before the "interrupt" mode is acknowledged, requiring a waiting period corresponding to 100 copies. This is a substantial time period.
Continuing with Connin, assume that in the noncollating mode as in the example above, there are 100 original documents in the stack, that the first original document has been fed to the document viewing glass and that the task requires 999 copies of each original document. Before each exposure, the system control checks to see if the "interrupt" mode has been selected and a decision is made to going into the "interrupt" mode. However, at this point, the "interrupt" mode is not acknowledged. In fact, it is not acknowledged until all of the 999 copies of the first document have been made requiring a waiting period corresponding to 999 copies. This is a prohibitive time period.
To sum up, the collate mode, the "interrupt" mode can only be acknowledged after the making of a complete copy set at which point the "interrupt" will be acknowledged. In the noncollate mode, all copies of the original document at the document viewing glass will be made before the "interrupt" mode can be acknowledged. Moreover, in Connin a single document feeder is dedicated to two tasks which further limits the effectiveness of the "interrupt" mode as disclosed.
Accordingly, there is a need in the prior art in the situation of one or more input devices or modes operating in a collate or noncollate mode having "interrupt" capability to be able to immediately acknowledge an "interrupt" mode, in the case of a collate mode, before the completion of a copy set, and in the case of a noncollate mode, before the completion of the copying of the original document at the document viewing glass in order to increase copy throughput and enhance human factors. Additionally, there is a need to increase throughput but yet enhance operational human factors by eliminating the dedication of two tasks to a single feeder.
Still another "interrupt" technique or, better denoted as an "interleaving" technique, i.e., only alternate feeding, between a RADF and a document positioner (DP), is disclosed in publication 17366 to Platt, entitled "Apparatus for Selectively Copying From Two Different Document Feeders", Research Disclosure, September 1978 No. 173, pg. 61 et seq. In Platt, a RADF having substantially the same structure as the feeder disclosed in Connin, is modified to include a DP which is suitable for feeding single original documents to a document viewing glass for copying one or more times, and then for ejecting the original documents from the document viewing glass along a non-recirculating path.
In addition, copies can be made either from the RADF or from the DP based on data furnished to a computer by an operator. In this mode of operation, the operator inputs appropriate data through only one of two control panels, a control panel being dedicated to each of the foregoing feeders, and places the original documents or document to be copied in the selected feeder. As disclosed, the RADF is dedicated to making collated sets of copies of an original document stack by recirculating each document once for each set desired, while the DP is dedicated to making noncollated copies of single original documents. However, as disclosed, if both feeders are used and formatted via their separate control panels, the DP can only process a single original document whereupon the RADF commences operation again. Then after an additional RADF feed cycle, the DP can process another original document and so on.
Herein lies the difference between what is understood to be an "interrupting" mode and an "interleaving" mode as disclosed in Platt. It should also be noted that in Platt, the DP has priority, i.e., it can delay operation of the RADF, a feed cycle at a time. Hence, if both feeders are loaded and both control panels are formatted, the DP feeds first. Nevertheless, after this first operation, there is no priority since feeding will be "interleaved" between the two feeders.
Hence, there is needed in the prior art not only to provide two document feeders so that original documents therefrom can be selectively copied, but to provide two document feeders not each dedicated to a particular task, to provide a true "interrupt" mode, in that a subsequent task regardless of its makeup or number of original documents can be continuously run on either of the two feeders, to provide means for "interrupting" either feeder, and to provide the foregoing by using only one control panel, thereby enhancing reliability, copy throughput and operational human factors and yet not limit task size or format.
The prior art and background, as indicated hereinabove, include some advances in the use of plural input modes and/or devices, and control of the modes or devices using "interrupting" and "interleaving" techniques to enhance operation of copier systems. However, no prior art system incorporates all of the features and advantages of the present invention.